1. Field of the Invention
The present invention relates to a fastening device of ski-boots.
2. Description of Background Art
It is known that one of the more widely used devices for fastening ski-boots comprises a plate provided with a plurality of identical, parallel, hooked-shaped seats and a metal ring with a substantially rectangular profile, one side of which is releasably engageable with one of the hook-shaped seats while the opposite side is pivoted to the end of a tightening unit. This tightening unit, in its turn, comprises a second-class lever pivoted on a plate-like base, and a rod-shaped tie having one end pivoted at the point of action of the lever and the other end connected to the aforementioned metal ring. Usually, the tie rod has a threaded end portion which is engaged with a nut fixed to the metal ring. By means of this screw and nut coupling, it is possible to adjust the tightness of the fastening.
Although advantageous from several aspects, due to the manner in which the tightness of the fastening is adjusted, this fastening device has a technical disadvantage which has not been overcome until now. In fact, for this adjustment, it is always necessary to disengage the ring from the respective hook-shaped seat and rotate it to operate the screw and nut coupling, and then re-engage the ring in the hook-shaped seat to check the degree of tightness of the fastening which has been achieved. The desired tightness is usually achieved after a number of these operations, which, when effected under unfavourable conditions, may be laborious and tiring to the extent that the user frequently does not complete the desired adjustment.